The present invention relates to an imaging device, for example, to an imaging device of a CMOS (Complementary Metal-Oxide Semiconductor) type.
A CMOS imaging device, or the so-called COMS imaging sensor, has spread widely in the field of a digital camera. When expanding the application of the COMS imaging sensor to a vehicle-mounted camera or a surveillance camera, enlargement of the dynamic range and also enhancement of the operation speed are required.
Patent Document 1 and Patent Document 2 both disclose a solid-state imaging device in which pixels are integrated in the shape of an array. Each of the pixels is configured with a photodiode which generates and stores a charge when subjected to light, a floating diffusion to which the charge stored in the photodiode is transferred, and a storage capacitance element which stores a charge overflowing from the floating diffusion. Patent Document 3 discloses an imaging device in which pixels are integrated in the shape of an array. In each of the pixels, four photodiodes are coupled to a gate of an amplification transistor via four transfer transistors, respectively, and the output of the amplification transistor is fed externally via a select transistor.
Non Patent Literature 1 discloses a technology to enlarge the dynamic range and a configuration of an image sensor in which a single slope integrating A/D converter is integrated.
Non Patent Literature 2 discloses a pixel circuit having a lateral overflow integration capacitor (LOFIC) structure.